Hound is an extremely fast source code search engine. The core is based on this article (and code) from Russ Cox: Regular Expression Matching with a Trigram Index. Hound itself is a static React frontend that talks to a Go backend. The backend keeps an up-to-date index for each repository and answers searches through a minimal API.

Starting April 21, we will be expanding our use of mobile-friendliness as a ranking signal. This change will affect mobile searches in all languages worldwide and will have a significant impact in our search results. Consequently, users will find it easier to get relevant, high quality search results that are optimized for their devices.

lunr.js is a simple full text search engine for your client side applications. It is designed to be small, yet full featured, enabling you to provide a great search experience without the need for external, server side, search services.

lunr.js has no external dependencies, although it does require a modern browser with ES5 support. In older browsers you can use an ES5 shim, such as augment.js, to provide any missing JavaScript functionality.